Apparatus for use in wells



Aug. 29, 1961 M. E. TRUE APPARATUS FOR USE IN WELLS 2 Sheets-Sheet 1Filed Dec. 15, 1958 POWER SOURCE CAM FOLLOWER CAM SURFACE F I G. 4.

FIRING /26 LINE OF FIRE F I G. 6.

DETECTOR INDICATOR Fl G. 2.

INVENTOR. MARTIN E. TRUE DETZECTOR 22 SHlELD--" 23 SOURCE" E Aug. 29,1961 M. E. TRUE 2,998,068

APPARATUS FOR USE IN WELLS Filed Dec. 15, 1958 2 Sheets-Sheet 2 sumsspnme CAM FOLLOWE PATH 0F CAM FOLLOWER GUIDE SPRING POSITION 40 FIG. 5.

INVENTOR. MARTIN E.TRUE,

ATTORNEY.

United States Patent M 2,998,068 APPARATUS FOR USE IN WELLS Martin E.True, Houston, Tex., assignor, by mesne assignments, to JerseyProduction Research Company, Tulsa, Okla., a corporation of DelawareFiled Dec. 15, 1958, Ser. No. 780,343 1 Claim. (Cl. 16655) Thisinvention generally concerns multiple zone well operations. Moreparticularly, the invention concerns apparatus for orienting a gunperforator in order to direct the fire thereof in a selected direction.

In multiple Zone well operations, a plurality of pipe strings arearranged in a borehole which penetrates a plurality of productiveintervals and production fluids from each interval are conductedindependently to the earths surface through these pipe strings. In orderto perforate a particular interval, a gun perforator is run in theborehole and fired in a direction to cause penetration of the formation.However, when at least two pipe strings are positioned adjacent theinterval to be perforated, it is necessary to direct the fire of the gunperforator in order to avoid striking any one of the pipe strings otherthan the pipe string through which the gun perforator is run. Also, inwell operations whereinthe borehole contains a plurality of pipestrings, it may be desired to direct the fire of the gun perforator toperforate one or more of the pipe strings in certain instances as, forexample, when it is necessary to establish subsurface communicationbetween pipe strings during blowouts, workovers, etc.

These purposes are achieved by the present invention which, briefly,provides apparatus for perforating in a well bore penetrating asubsurface formation, said well bore having at least two eccentric,spaced-apart pipe strings arranged therein comprising a gun perforatorhaving a selected direction of fire arranged in one of said pipestrings; means for rotatably positioning said gun perforator to directthe direction of fire thereof in any selected direction in a 360 arc andmeans for detecting the location of at least one other pipe stringrelative to the direction of fire in order to avoid perforation of saidother pipe string or to perforate said other pipe string which everprocedure is desired.

The invention is advantageous over known devices for positioning thedirection of fire of a gun perforator in that the use of gun guides isavoided; it permits maintaining full openings throughout the pipestrings; it eliminates the possibility of incorrect orientation should apipe string rotate or slip in a clamp or should it be misaligned byerror; and it permits running pipe strings in the well bore separately.

These purposes and other purposes of the invention will be apparent froma description thereof taken in conjunction with the drawings wherein:

FIG. 1 is a cross-sectional view of the earths subsurface showing aborehole having arranged therein two pipe strings, one of which containsthe gun perforator, the positioning assembly, and the pipe locatorapparatus; also shown schematically is surface equipment for 10- catingpipe and for firing the gun perforator;

FIG. 2 is a vertical, partly sectional, view of the gun perforatorpositioning assembly of FIG. 1;

FIG. 3 is a plan view taken on lines 3-3 of FIG. 2;

FIG. 4 is a plan view taken on lines 44 of FIG. 2;

FIG. 5 is an enlarged fragmentary view of the gun perforator positionerassembly of FIG. 2;

FIG. 6 is a plan view illustrating one manner of orientation accordingto the invention when the borehole contains two pipe strings; and

FIG. 7 is a plan view illustrating one manner of lfatented Aug. 29,1961

orientation when the borehole contains more than two pipe strings.

Referring to the drawings in greater detail, in FIG. 1 is shown aborehole 10 penetrating a subsurface formation 11. Two spaced-apart pipestrings 1'2 and 13 are arranged in borehole 10 and are cemented thereinby means of cement 14. A perforator tool, generally designated 15, issuspended in pipe string 12 on a multi electrically conductive cable 16.Tool 15 includes a pipe detector section 17, a gun positioner section18, and a gun perforator section 19. Section '17 includes a source ofradiation 20, a radiation detector 21 provided with a collimating shield22 and a shield 23 positioned therebetween. Section 19 includes gunelements 24 which may be any desired type of gun perforator, such as thejet type or the bullet type. Cable 16 extends to the surface of theearth where it electrically connects to a detector indicator 25, afiring device 26, and a source of power 27.

Details of section 18, shown more clearly in FIG. 2, include a mandrel28 provided with a cam follower 29; a cage 30 provided with a camsurface 31 and arranged on mandrel 18 in a manner such that cam follower29 rides on cam surface 31; and drag springs 32 adapted to frictionallyengage the interior wall of pipe string 12 to restrain movement of cage30. As seen more clearly in FIG. 5, the cam surface 31 is configuredgenerally in the form of alternately inverted Ys which extend fullyabout cage 30 to form a continuous path. For purposes of illustration,the width of each Y is shown to be 60; however, any desired increment ofdegrees may be employed. Leaf spring guides as, for example, guides 33to 37 are positioned at various junctures of the path as shown.

FIGS. 3 and 4 illustrate, also, the spacing of the cam surface Ys.

When it is desired to position the direction of fire of gun elements 24in any desired direction as, for example, to direct the fire thereof toavoid striking pipe string 13, tool 15 is lowered through pipe string 12until it is positioned adjacent formation 11. Cable 16 then is raisedand lowered thereby causing cam follower 29 to travel on cam surface 31.Referring to FIG. 5, starting with cam follower 29 at the positiondesignated 40 raising of cable 16 raises mandrel 28 and attached camfollower 29 and causes the cam follower 29 to travel upwardly in path41. It is guided past the juncture of paths 41 and 42 by means of leafspring 34 which is biased against path 42. When cam follower 29 reachesthe juncture of paths 41 and 43, it moves past leaf spring 35 againstthe bias thereof into the upper portion of path 43 until it reaches theupper end thereof. Then, cable 16 is lowered thereby lowering mandrel 28and attached cam follower 29 and in its downward travel through path 43,leaf spring 35 guides the cam follower by path 41. Cam follower 29 inits downward travel at the juncture of paths 43 and 44 forces leafspring 36 open against the bias thereof and cam follower 29 is loweredto the lower end of path 44. This manner of raising and lowering of camfollower 29 is continued and a complete 360 revolution or manyrevolutions may be made. While mandrel 28 is rotated, section 17 andsection 19 are also rotated. At any point during the 360 traverse, thecollimated detector may be employed to detect induced radiationresulting from the bombardment of the surrounding area by radiationsource 20. Shield 22 is designed to restrict the arc of detection to aselected are as, for example, 45. Shield 23 insures that only inducedradiation is detected by detector 21. Detector indicator 25 indicatesthe presence of pipe string 13 when detector 21 is focused thereon. Ifdesired, the bombardment and detection of radiation may be continuouslymade during the 360 traverse by camfollower 29 to establish the locationof pipe string 13 relative to the direction of detection. The directionof detection relative to the direction of fire of gun elements 24 isknown. Consequently, the direction of fire of gun elements 24 relativeto the position of pipe string 13 is established. The gun perforator maybe then rotated by raising and lowering cable 16 until the gunpenforator 'is positioned so as to direct the fire of the gun elements24 away from pipe string 13. A situation of this nature is illustratedin FIG. 6 wherein the direction of fire 50 of gun elements 24 isdirected away from pipe string '13.

In a similar manner, other pipe strings may be avoided. This situationis illustrated in FIG. 7 wherein the direction of fire 50 of gunelements 24 is positioned to fire away from both pipe strings 39 and 13.

The particular technique for detecting pipe strings shown anddescribedwith regard to the operation of the invention may besubstituted by other arrangements; for example, the radiation source maybe focused instead of or in conjunction with focusing of the detector;the detector may be arranged in the pipe string to be detected; thesource may be arranged in the pipe string to be detected; and soforth.

The source of radiation 20 may be fast neutrons or gamma rays. Thus, thesource maybe an alpha-neutron, deuteron-neutron, or proton-neutronreaction wherein the alpha particle, deuteron, or proton is acceleratedby an electric field and thereby caused to interact with selected targetmaterials in order to produce neutrons of various energies within theconfines of source 20; or the radiation may be neutrons originating froma radiumberylliurn or prolonium-beryllium source. Sources of high energygamma radiation which may be employed are radioactive Na La Sb Co, orhigh energy gamma rays produced by various reactions in high energyparti-cle machines in a manner well known to the art of nuclear physics.For example, the bombardment of lithium by protons produces high energy17 mev. gammas.

Detector '20 detects slow neutrons or gamma rays or fast neutrons andfor the detection of this radiation ionization chambers, Geiger-Muellertubes, and scintillation counters may be used.

Shields 22 and 23 are formed ofradiation absorbing materials such aslead, tungsten, paraflim-boron, cadmium, etc., which materials arecapable of absorbing the induced radiation to be detected. Theinvention'is applicable to so-called tubingless completions; that is,wells completed without setting casing. This method, which isillustrated in FIG. 1, includes running the required pipe strings and icementing the pipe strings in place. The invention may be also employedin cased wells; that is, in wells where a casing is run and cemented inplace and pipe strings are arranged Within the casing.

In the instances wherein a plurality of pipe strings are arranged in theborehole to insure that the direction of fire of the gun perforator isaway from all of the pipe strings except the one in which the gunperforator is arnanged, it is preferable to direct the fire in only onedirection. In instances of this nature, also, instead of having thedirection of detection opposite to or other than the direction of fire,it may be preferable to have the direction of detection coincide withthe direction of fire.

Although the description of the invention relates to perforating theformation and avoiding striking other pipe strings arranged in the wellbore, the invention is not to be so limited; that is, as mentionedpreviously herein, the invention may be employed for perforatingselected pipe strings in the well bore. 7

Having fully described the operation, objects, and apparatus of myinvention, I claim:

Apparatus for perforating in a well bore penetrating subsurfaceformations, said well bore having at least two spaced-apart pipe stringsarranged therein comprising a gun perforator having a selected directionof fire arranged in one of said pipe strings; gun perforator positioningmeans adapted to position said gun perforator to direct the direction offire thereof in any selected direction in a 360 are including cage meansprovided with a cam surface configured in the shape of alternatelyinverted Ys and also provided with means for engaging the interior wallof said one pipe string to restrain movement of said cage means; meansconnected to said gun perforator and provided with a cam followeradapted to ride on said cam surface; guide means arranged on said camsurface adapted to guide said cam follower to move in only onecircumferential direction; and means for detecting the location of atleast one other pipe string relative to said direction of fire.

References Cited in the file of this patent- UNITED STATES PATENTS2,178,540 McNeese et a1 Nov. 7, 1939 2,316,361 Piety Apr. 13, 19432,400,970 Baker May 28, 1946 2,429,910 Anderson et al Oct. 28, 19472,781,098 Bielstein Feb. 12, 1957 2,785,754 True Mar. 19, 1957

